Use of a Lactobacillus casei assay as a prescreen for potential anticancer agents: an update study.

Updating an earlier report, 15 known antineoplastic agents, 11 of which are commercially available for treatment of human cancers, were tested for growth-inhibitory activity in a Lactobacillus casei system to determine if this microbial system could select them as "active." Although we previously reported that over 160 compounds tested in this assay were inactive, 11 of the 15 known antineoplastic agents tested here were inhibitory. Because of this observation and the advantage that the procedure is rapid and inexpensive, this microbiological assay is recommended for consideration as a prescreen for anticancer agents.

Potential CNS antitumor agents VI: aziridinylbenzoquinones III.

Thirty-one aziridinylbenzoquinones were compared against five murine tumor models in vivo. Two intracerebral (ependymoblastoma and L-1210 leukemia) and three intraperitoneal (P-388 and L-1210 leukemia and B16 melanoma) systems were utilized. Excellent activity was observed for many compounds. Multiple long-term survivors were produced in the ependymoblastoma, P-388, and intraperitoneal L-1210 systems. Diethyl 2,5-bis(1-aziridinyl)-3,6-dioxo-1,4-cyclohexadiene-1,4-dicarbamate demonstrated superior activity in all five test systems. This compound also was reproducibly active against two colon tumors, a mammary tumor, and the intracerebrally implanted P-388 leukemia model.

Combination chemotherapy against B16 melanoma: bleomycin/vinblastine, bleomycin/cis-diamminedichloroplatinum, 5-fluorouracil/BCNU and 5-fluorouracil/methyl-CCNU.

Four antitumor drug combinations which are currently in clinical use were evaluated experimentally using the murine B16 melanoma model. Bleomycin plus vinblastine produced an increase in life span over either of the two agents alone against both intraperitoneal and subcutaneous B16. This combination also resulted in a large number of long-term survivors. Bleomycin plus cis-platinum produced slight enhancement against subcutaneous B16, but showed no advantage against intraperitoneal B16. The combination of 5-fluorouracil plus methyl-CCNU significantly increased survival time against the intraperitoneal tumor, and produced long-term survivors as well. The combination of 5-fluorouracil plus BCNU was not more effective than BCNU or 5-fluorouracil alone. These data were compared with the degree of success reported from the clinics against a variety of solid human neoplasms.

Characterization and responsiveness of the Madison 109 lung carcinoma to various antitumor agents.

The Madison 109 (M109) tumor was discovered in 1964 in the lung of a BALB/c mouse. This experimental carcinoma is maintained in vivo by sc passage in the right axillary region. When implanted im (5 X 10(5) cells) into the right hind leg of BALB/c mice for testing, the primary progresses with metastases to the lung, spleen, and liver. The metastases to the lung are visible within 3 weeks and result in the death of the host in about 35 days after tumor implant. Implantation of a lung nodule is tumorigenic and lethal. Pyran polymer therapy delayed the appearance of lung metastases, inhibited the growth of the primary tumor, and significantly increased the lifespan of BALB/c mice inoculated with the M109 tumor. No spontaneous regression has been observed and very few "no takes" have occurred in untreated BALB/c mice inoculated with at least 500 M109 cells. Of the 82 agents tested so far, the M109 model has selected active agents such as actinomycin D, adriamycin, daunorubicin, DNA, procarbazine, and pyran polymer. It has not shown sensitivity as tested to several standard therapeutic agents including cytosine arabinoside, BCNU, hydroxyurea, mechlorethamine, melphalan, triethylenemelamine, and vincristine.

A statistical-heuristic methods for automated selection of drugs for screening.

A statistical-heuristic method for selecting drugs for animal screening is developed with molecular structure features as predictors of biological activity. The method is intended to work on large amounts of data over varied structures. A trial of this method on a small data set allows some comparison with more sophisticated pattern recognition methods. Problems connected with interdependence among structure predictors are critical in this method and schemes to eliminate redundancy are reviewed. Alternate sets of structure predictors are considered. The discussion here outlines directions to be taken in the near future.

Pattern recognitiion and structure-activity relationship studies. Computer-assisted prediction of antitumor activity in structurally diverse drugs in an experimental mouse brain tumor system.

This paper reports the application of pattern recognition and substructural analysis to the problem of predicting the antineoplastic activity of 24 test compounds in an experimental mouse brain tumor system based on 138 structurally diverse compounds tested in this tumor system. The molecules were represented by three types of substructural fragments, the augmented atom, the heteropath, and the ring fragments. Of the two pattern recognition methods used to predict the activity of the test compounds the nearest neighbor method predicted 83% correctly while the learning machine method predicted 92% correctly. The test structures and the important substructural fragments used in this study are given and the implications of these results are discussed.